It's a great thing to adjust faders in the instruments window without having to go into the instruments window........it can sit in the background and you can adjust the faders and pan controls while inside another window.
Would it be possible to play the keyboard in the graphic editor without being in the window? Then you could be in sampletank adjusting an effect on an instrument and hear the result without having to go between the 2 windows. A great idea for hearing minute changes between 2 settings quickly.